On Sun, 11 Feb 2018, Martin Blumenstingl wrote:

> The USB HCD core driver parses the device-tree node for "phys" and
> "usb-phys" properties. It also manages the power state of these PHYs
> automatically.
> However, drivers may opt-out of this behavior by setting "phy" or
> "usb_phy" in struct usb_hcd to a non-null value. An example where this
> is required is the "Qualcomm USB2 controller", implemented by the
> chipidea driver. The hardware requires that the PHY is only powered on
> after the "reset completed" event from the controller is received.
> A follow-up patch will allow the USB HCD core driver to manage more than
> one PHY. Add a new "bool skip_phy_initialization" field to struct
> usb_hcd so drivers can opt-out of any PHY management provided by the USB
> HCD core driver. The new field will be used in that patch as well.
> This also updates the existing drivers so they use the new flag if they
> want to opt out of the PHY management provided by the USB HCD core
> driver. This means that for these drivers the new "multiple PHY"
> handling (which will be added in a follow-up patch) will be disabled as
> well.
> Signed-off-by: Martin Blumenstingl <martin.blumensti...@googlemail.com>
> ---

> --- a/include/linux/usb/hcd.h
> +++ b/include/linux/usb/hcd.h
> @@ -98,6 +98,12 @@ struct usb_hcd {
>        */
>       const struct hc_driver  *driver;        /* hw-specific hooks */
> +     /*
> +      * do not manage the PHY state in the HCD core, instead let the driver
> +      * handle this (for example if the PHY can only be turned on after a
> +      * specific event)
> +      */
> +     bool skip_phy_initialization;

Instead of declaring this as a bool at some random location in the
structure, it would be better to make this a bitflag along with the
other ones that get set at registration.  For example, it could come
right after the remove_phy flag.

Alan Stern

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